P1539: INFECTION-RELATED MORTALITY CLINICAL-BIOLOGICAL SCORING SYSTEM (IRM-SCORE) AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION: A VALIDATION STUDY IN GITMO CENTRES
Authors: Daniela Clerici, Carmine Liberatore, Paola Maria Rancoita, Chiara Maria Dellacasa, Francesca Patriarca, Paolo Corradini, Riccardo Saccardi, Angelo Michele Carella, Stella Santarone, Maurizio Musso, Anna Paola Iori, Patrizia Chiusolo, Francesco Onida, Nicola Mordini, Marco De Gobbi, Piero Galieni, Mario Luppi, Massimo Aglietta, Daniele Vallisa, Gabriella Storti, Luca Facchini, Jacopo Peccatori, Annalisa Ruggeri, Raffaella Greco, Consuelo Corti, Francesca Bonifazi, Fabio Ciceri
Journal: HemaSphere (2023)

Topic: 30. Infections in hematology (incl. supportive care/therapy) Background: Infection-related mortality (IRM) remains a major issue in the context of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Recent improvement in supportive care have resulted in a considerable reduction of the treatment-related mortality, even though more effective prophylactic strategies and interventions are warranted. In a previous monocentric study a prognostic clinic-biological scoring system, based on four pre-transplantation factors (patient age, IgA and IgM levels, patient and donor CMV serostatus), was developed in order to predict IRM after allo-HSCT [Forcina et al, Biol Blood Marrow Transplant 23 (2017) 2151–2158]. This score identified 3 groups of patients with significant difference in term of IRM (low, intermediate and high-risk group). Aims: We aimed to promote IRM-score prognostic validation in a multicenter setting in centres of the Gruppo Italiano Trapianto Midollo Osseo (GITMO). Methods: Adult patients (18 -78 years), undergoing first allo-HSCT for both malignant and non-malignant hematologic diseases between 1st January 2012 and 31st May 2015, have been enrolled. A cohort of 1241 patients had completed data for being analyzed. Patients were clustered according to the 3-tiered prognostic model developed by Forcina et al. into 3 risk classes: low-risk <10.17 points; intermediate-risk 10.17 – 11.11 points, and high-risk >11.11 points. Primary endpoint was validation of this IRM scoring system in a multicenter setting. Results: A total of 236 patients, belonging from the monocentric original-cohort used for the derivation of the score, have been included with longer updated follow-up. This original-cohort has been compared with a new multicenter-cohort of 1005 patients, employed for externally validating the prognostic score. Overall, median follow up was 46.45 months. The original-cohort showed the following main differences with respect to the multicenter-cohort: older age (p=0.0003), higher comorbidity score (p=0.003), higher incidence of pre-transplant MDR colonization (p=0.0002) and less patients with CMV negative/negative serostatus (p=0.0155). Overall, IRM score was: low-risk in 550 (44.32%), intermediate-risk in 362 (29.17%), and high-risk in 329 (26.51%) patients. Notably, risk groups were differently distributed between cohorts, with a higher proportion of low-risk patients and a lower proportion of intermediate-risk patients in multicenter versus original-cohort (p=0.0389). Globally, the risk groups showed a significantly different IRM in both cohorts (p<0.0001 for original-cohort and p=0.0068 for multicenter-cohort) (Fig.1). In the original-cohort, IRM at 100-days was: 5% in low-risk, 9% in intermediate-risk, and 28% in high-risk group. In multicenter-cohort, IRM at 100-days was: 5% in low-risk, 8% in intermediate-risk, and 7% in high-risk group. In the original-cohort, IRM at 2-years was: 10% in low-risk, 23% in intermediate-risk, and 40% in high-risk group. In multicenter-cohort, IRM at 2-years was: 9% in low-risk, 12% in intermediate-risk, and 17% in high-risk group. Summary/Conclusion: Both the original-cohort with extended follow-up and the new multicenter cohort confirmed that the IRM score is reliable, cost-effective and applicable accross different transplant settings. IRM score may provide a useful clinical tool for the early identification of HSCT recipients at highest risk of infection mortality and application of tailored prophylactic/pre-emptive strategies. Fig.1Keywords: Bone marrow transplant, Infection